It always strikes me as odd that the geoengineering experiment that got us into the predicament (dumping boatloads of CO2 into the atmosphere), the politics were so much easier.
Dumping boatloads of CO2 into the atmosphere is second order from the actual goal of producing electricity so most people just can't/don't/won't think about it.
In this case we'd be intentionally dumping SO2 so people are capable of thinking "wow that's not moral" or whatever issue they might have with it.
Don't want to accidentally start an ice age by trying to prevent a hothouse planet from forming :P
Or maybe if some billionaire could figure out a way for their space-tourism project to “accidentally” produce SO2, then we’d give them the moral mulligan.